# Why do many people prefer roll-high to roll-under?

#### DrunkonDuty

##### he/him
I have an unreasonable dislike of roll under percentile systems. No idea why.

#### Swanosaurus

Rolling over just feels better.
In addition to "addition being easier than subtraction", and "Bigger is better", you also can get the feeling of "Breaking the power scale."

For example, a +1 bonus on a d10 roll allows you to get the feeling of "11 out of a Ten point scale, above and beyond" even if the game math means you aren't actually doing it. As a more extreme example, you could also stack bonuses to the point where you overpower basically overpower the die itself, feeling like you are cheating fate somehow.
That's actually something that I don't like that much ... the idea of "breaking the scale" confuses me about what the numbers actually mean. With roll-under-systems it's clear that a 15 out of 20 means, well, 15 out of 20 - which actually retains one element of "more is better", because 15 out of 20 is better than 5 out of 20; and it adds a scale that tells me how good 15 is. 15 on an open-ended scale could mean anything, I need to be more familiar with the system to know.

##### Heretic of The Seventh Circle
I do think that fiddly modifiers are part of the problem when one looks at the bigger picture. Earlier in this thread I said:

Because when "bigger numbers are better", game designers tend to provide different ways for you to make your character's numbers go up or for the GM to adjust those numbers as well. That's the common design answer in the market. And, again in my experience, it can lead to numbers inflation as well as increased math in the game.

I am more interested in the praxis of "roll over/under games" in concrete game systems rather than a pure abstraction of "higher is better" or "higher is more intuitive."
Okay
Unless you are letting these modifiers dip results into the negatives - which becomes the exact same system as roll high! - you will need to take steps to keep the results as close to the positive side of zero as you can. Making a lot of modifiers ultimately worthless. 5th edition essentially moves in this direction with its commitment to bounded accuracy.
You…seriously?
I said that it would most likely be modifiers to the static number, not to the die roll, if we want to imagine a system of modifiers just as fiddly as the worst offenders of d20 games.

I explicitly was not talking about modifying the roll.
Now that I mull that over, I think it's pretty important. In a roll-over system, there's no conceptual limit to how high you can roll. In a roll under system, optimal success is "as close to your target as possible" whether the target is zero or your skill level.
Except that you can…modify…the target number.

If a bonus in RL D&D would give you a +5 to Acrobatics checks? Low-roll D&D would give a +5 bonus to your Acrobatics skill, making it easier to roll under.

And you’re replying to some detail of an example instead of the point. Why? What purpose does it serve?

#### kigmatzomat

##### Hero
As someone who loves earthdawn, roll under sets a finite bounding box on the level of success. ED rejects the notion of impossibility and allows a toddler to poke a dragon's eye out with a well-thrown pacifier.

It's a game with success levels & rerolling dice that max, meaning I have a (very) small chance of rolling so incredibly high to get an absurd success level (the aforementioned toddler), which can even result in creating a magic item on the spot (The "Pacifier of Cutiepie")

Doing the same with roll-under requires negative numbers and "imploding" dice, which is notably harder to implement than "exploding" dice. "Okay I rolled an 01 vs 50! Time to implode, so I reroll and rolled another 01! Wait, does that mean I got a 0? No, wait it's a (50-1) + (50-1) but shoot, I got to roll again so also (50- my next roll)...."

#### kigmatzomat

##### Hero
That's actually something that I don't like that much ... the idea of "breaking the scale" confuses me about what the numbers actually mean. With roll-under-systems it's clear that a 15 out of 20 means, well, 15 out of 20 - which actually retains one element of "more is better", because 15 out of 20 is better than 5 out of 20; and it adds a scale that tells me how good 15 is. 15 on an open-ended scale could mean anything, I need to be more familiar with the system to know.

That's an illusion. Those aren't PC odds, those are "typical" people odds for checks performed under "typical" circumstances able to take a "typical" amount of time. PCs are atypical people in atypical circumstances trying to do atypical things where modifiers abound (improvised tools, rushed job, distracted, in a snow storm, uphill, both ways)

You have to be familiar with the system, and the challenges, to know what your "real" odds are.

#### Swanosaurus

That's an illusion. Those aren't PC odds, those are "typical" people odds for checks performed under "typical" circumstances able to take a "typical" amount of time. PCs are atypical people in atypical circumstances trying to do atypical things where modifiers abound (improvised tools, rushed job, distracted, in a snow storm, uphill, both ways)

You have to be familiar with the system, and the challenges, to know what your "real" odds are.
Doesn't depend that on the system? I mean, sure, these are odds for "adventure" situations, but I still like to have a fixed scale on which to judge them.

#### Committed Hero

And you’re replying to some detail of an example instead of the point. Why? What purpose does it serve?
My point is that roll under and roll over are not opposites. The probabilities may be the same, but the mechanics are fundamentally different.

I don't think it makes a difference in a percentile system if you are modifying the roll or the range. Whether you focus on zero or the target number, you run into the same issues at either end.

#### John Dallman

##### Hero
A supplementary question. Back in the 1980s, I never ran into anyone who had strong opinions about the virtues of roll-high vs roll-under. Why might that have been?

One obvious possibility is chance: gamers had far less communication with each other in the days before the Internet, so possibly I just didn't encounter it. However, I've been using online TTRPG forums since 1992, and never encountered it being discussed before the early 2000s.

#### Crimson Longinus

##### Legend
A supplementary question. Back in the 1980s, I never ran into anyone who had strong opinions about the virtues of roll-high vs roll-under. Why might that have been?

One obvious possibility is chance: gamers had far less communication with each other in the days before the Internet, so possibly I just didn't encounter it. However, I've been using online TTRPG forums since 1992, and never encountered it being discussed before the early 2000s.
I don't think the importance of system aesthetics was much understood back then. People were used to game mechanics being arbitrary incoherent messes like AD&D.

#### Committed Hero

A supplementary question. Back in the 1980s, I never ran into anyone who had strong opinions about the virtues of roll-high vs roll-under. Why might that have been?

The d20 framework gave publishers an incentive to use it for everything at the same time you noticed the opinions. Prior to that, Steve Jackson and Chaosium weren't necessarily trying to push their universal roll-under systems into competition for D&D players.

And as Crimson Longinus notes, 1st/2nd edition D&D was a roll over system for some things and a roll under system for others.

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